10,709 research outputs found

    The biomechanical function of periodontal ligament fibres in orthodontic tooth movement

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    Orthodontic tooth movement occurs as a result of resorption and formation of the alveolar bone due to an applied load, but the stimulus responsible for triggering orthodontic tooth movement remains the subject of debate. It has been suggested that the periodontal ligament (PDL) plays a key role. However, the mechanical function of the PDL in orthodontic tooth movement is not well understood as most mechanical models of the PDL to date have ignored the fibrous structure of the PDL. In this study we use finite element (FE) analysis to investigate the strains in the alveolar bone due to occlusal and orthodontic loads when PDL is modelled as a fibrous structure as compared to modelling PDL as a layer of solid material. The results show that the tension-only nature of the fibres essentially suspends the tooth in the tooth socket and their inclusion in FE models makes a significant difference to both the magnitude and distribution of strains produced in the surrounding bone. The results indicate that the PDL fibres have a very important role in load transfer between the teeth and alveolar bone and should be considered in FE studies investigating the biomechanics of orthodontic tooth movement. © 2014 McCormack et al

    Effect RANKL Produced by Periodontal Ligament Cells on Orthodontic Tooth Movement

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    The bone remodeling process involved in orthodontic tooth movement consists of bone resorption on the compression side and bone formation on the tension side of the teeth. Osteoclasts play an important role in bone remodeling and are necessary for orthodontic tooth movement. Receptor activator of nuclear factor-κB ligand (RANKL) is essential for osteoclast formation and differentiation. Several cell types have been reported to be capable of producing RANKL. We are interested in whether there is a dominant cell type which RANKL production is critical in generating orthodontic tooth movement. In this study, we used a Cre recombinase mouse model to study the effect of RANKL deletion in periodontal ligament cells on orthodontic tooth movement. We found RANKL deletion in periodontal ligament cells significantly decreased the amount of orthodontic tooth movement and reduced the number of osteoclasts formed on the compression side after subjecting the teeth to orthodontic force. It suggests RANKL production from periodontal ligament cells contributes greatly to orthodontic tooth movement and serves as an important source of RANKL in osteoclastogenesis during orthodontic tooth movement

    Periodontal Tissue Remodeling Incident to Experimental Tooth Movement

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    Changes of periodontal tissues incident to experimental tooth movement in vivo and mechanical stress on bone tissue in vitro as well were explained and discussed in this article from the point of view of orthodontic treatment. These following items were introduced, based on results of basic and clinical researches. 1) Histological structures of periodontal tissues and reaction of the tissues incident to experimental tooth movement in vivo 2) Tissue and cellular reaction related to mechanical stimulus in vitro 3) Recent topics of osteoclastogenesis inhibitory factor (OCIF) and osteoclast differentiation factor (ODF) related to molecular biology 4) Prostaglandins as a mediator for bone resorption during orthodontic tooth movement 5) Recent topics of orthodontic application for bone morphogenetic protein (BMP) 6) Application of results from the basic research of tooth movement on orthodontic treatment, such as optimum force, effective tooth movement and pharmacological anchorag

    Cell Lineage Tracing of Osteoblasts Within the Periodontal Ligament During Orthodontic Tooth Movement

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    Background: The periodontal ligament is known to play a role in the bone remodeling response to orthodontic tooth movement and to contribute specifically to osteogenic cell populations involved in this process. Cell lineage tracing is a technique which enables the tracking of specific cell populations throughout differentiation in vivo. 3.2kbCol1α1 is present in early osteoblastogenesis and can therefore be used to trace osteoblasts and similar related osteogenic cells. Purpose: The purpose of this study was to a) create a valid murine model of orthodontic tooth movement and, b) orthodontically treat temporally inducible cell lineage tracing mice to study osteoblasts response within the periodontal ligament. Materials and methods: 3.2Col1α1 mice were used in this study. Orthodontic appliances were bonded between the maxillary first molar and the maxillary incisors to induce mesial movement of the maxillary first molar. The mesial root of the maxillary first molar was used for evaluation in this study. 5 groups of mice were studied with 4 mice in each group; group 1: no induction, no orthodontic treatment; group 2: induction, no orthodontic treatment; group 3: induction, 1-day orthodontic treatment; group 4: induction, 2-day orthodontic treatment; group 5: induction, 4-day orthodontic treatment. Radiological analysis was performed. Angle of first molar was quantified to determine presence of tooth movement. Mean widths of periodontal ligament were compared. 3.2Col1α1 signal was characterized. H&E staining and anti-Ki67 and anti-CathepsinK immunofluorescent staining was performed. Results: Orthodontic treatment induced orthodontic tooth movement. 3.2kbCol1α1-positive cells were identified within the periodontium. The number of 3.2kbCol1α1- positive cells increased in response to orthodontic treatment. Ki67 expression was inversely related to length of orthodontic treatment. CathepsinK activity was inconclusive regarding the determination of a relationship between 3.2kbCol1α1-positive osteoblast patterning and osteoclast activity. Conclusions: 3.2kbCol1α1-positive cells are present in the periodontal ligament and increase in response to orthodontic tooth movement

    Overview of platelet-rich plasma: Orthodontics perspective

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    Background: Platelet-rich plasma (PRP) is an autologous concentration of human platelets in a small volume of plasma. It comprised several fundamental growth factors which actively work for the initiation of the wound healing process of both soft and hard tissues. PRP in dentistry is in use since 1998 for many reasons, one of which is the orthodontic tooth movement. Many studies have been performed to check the role of PRP in orthodontic tooth movement and most of them found it is an effective method with fewer drawbacks compared to other methods. Aim: This article aims to highlight the effects of PRP in orthodontic tooth movement. Conclusion: PRP is an effective and simplest method to accelerate orthodontic tooth movement. Clinical significance: It can be used to reduce the time for treatment by incorporating it into our routine treatment practice

    Orthodontic Force Application in Correlation with Salivary Lactate Dehydrogenase Activity

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    Orthodontic tooth movement generate mechanical forces to periodontal ligament and alveolar bone. The forces correlate with initial responses of periodontal tissues and involving many metabolic changes. One of the metabolic changes detected in saliva is lactate dehydrogenase (LDH) activity. Objectives: To evaluate the correlation between orthodontic interrupted force application, lactate dehydrogenase activity and the distance of tooth movement. Methods: upper premolar, pre-retraction of upper canine and 1, 7, 14, 21 and 28 days post-retraction of upper canine with 100g interrupted orthodontic force. Results: duration of force (F=11.926 p 14 and 28 days post-retraction of canine. The region of retraction correlated with the distance of tooth movement (F=7.377 p=0.007). The duration of force correlated with the distance of tooth movement (F=66.554 p=0.000). retraction of canine. Conclusion: This study concluded that orthodontic interrupted force application on canine could increase the distance of tooth movement and LDH activity in saliva

    Remote Corticotomy Accelerates Orthodontic Tooth Movement in a Rat Model

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    Introduction. With an increasing demand for orthodontic treatment for adult patients, orthodontic professionals are constantly seeking novel strategies and technologies that can accelerate tooth movement in order to shorten the treatment period. For instance, in recent years, the influences of different surgical techniques on orthodontic tooth movement in the ipsilateral side of surgery were intensively investigated. Here, we attempt to examine if corticotomy could also affect the rate of tooth movement in the contralateral side of the surgery by using a rodent model. Materials and Methods. 72 eight-week-old Sprague-Dawley rats were randomly divided into three groups as follows: The Control group (orthodontic treatment devices delivered only, no tooth movement), the orthodontic tooth movement (OTM) group (orthodontic treatment devices delivered and orthodontic treatment performed), and the Corticotomy + OTM group (remote corticotomy performed, orthodontic treatment devices delivered, followed by orthodontic treatment). The surgical procedure was conducted on the right side of the maxilla at the time of appliance placement and a force of 60 g was applied between the maxillary left first molar and maxillary incisors using nickel-titanium springs to stimulate OTM. The OTM distance and speed were tracked at 3, 7, 14, and 28 days post-surgery, followed by histological and immunohistochemical assessments. Results. In comparison with orthodontic treatment only, the contralateral corticotomy significantly accelerated OTM. Furthermore, animals undergoing corticotomy + OTM presented with a greater number of osteoclasts on the compression side, stronger staining of the osteogenic marker on the tension side, and higher expression of an inflammatory marker than the OTM group animals. Conclusion. Our current study demonstrates that remote corticotomy effectively accelerates alveolar bone remodeling and OTM. The study enriches our understanding of the regional acceleratory phenomenon (RAP) and offers an alternative strategy for accelerating OTM to shorten the orthodontic treatment period. © 2019 Min Zou et al

    Growth hormone receptor and IGF-1 receptor immunoreactivity during orthodontic tooth movement in the prednisolone-treated rat

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    Bone remodeling during tooth movement is regulated by local and systemic factors. Two regulators of bone metabolism are growth hormone (GH) and insulin-like growth factor-I (IGF-1). Their effects are mediated via binding to GH receptor (GHR) and IGF-I receptor (IGF-IR) in target tissues. Corticosteroids may affect the activity of these growth factors. This study examined the effect of prednisolone on GHR and IGF-IR expression in dental tissues following orthodontic tooth movement. The corti ticosteroid-treated group (N = 6) was administered prednisolone ( 1 mg/kg,) daily and the control group (N = 6) received equivalent volumes of saline. An orthodontic force (30 g) was applied to the maxillary first molar. Animals were sacrificed 12 days postappliance insertion. Sagittal sections of the first molar were stained for GHR and IGF-IR immunoreactivity. GHR and IGF-IR cell counts were elevated following appliance-treatment. Orthodontic tooth movement appeared to up-regulate GHR and IGF-IR immunoreactivity, but this up-regulation was reduced following prednisolone treatment. The suppression of GHR and IGF-I immunoreactivity in steroid-treated animals infers the mechanism whereby bone resorption and deposition, necessary for orthodontic tooth movement, may be inhibited by prednisolone. However, at 12 days postappliance insertion. no difference in orthodontic tooth movement was observed following low-dose prednisolone treatment

    Histomorphometric and Histopathologic Evaluation of the Effects of Systemic Fluoride Intake on Orthodontic Tooth Movement

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    Objectives The aim of this study was to determine the effects of systemic fluoride intake on orthodontic tooth movement with histomorphometric and histopathologic methods. Materials and Methods Forty-eight Wistar albino rats were randomly divided into four groups of 12 rats each. Group I received fluoridated water and underwent orthodontic tooth movement. Group II received fluoridated water and did not undergo orthodontic tooth movement. Group III received nonfluoridated water and underwent orthodontic tooth movement. Group IV received nonfluoridated water and did not undergo orthodontic tooth movement. At the beginning of the experiment (T1), impressions were taken from the maxilla of the rats in groups I and III under general anesthesia, and a NiTi closed coil spring appliance was ligated between the left maxillary central incisors and maxillary first molar. The orthodontic force applied was approximately 75 g, and the duration of the experimental period was 18 days. During the experimental period, appliances were controlled daily. At the end of the experimental period (T2), the rats were sacrificed with an overdose of a ketamine/xylasine combination, and their impressions were obtained. The upper first molars were subsequently dissected for histological examination. Incisor–molar distance, number of osteoblasts, number of osteoclasts and periodontal ligament (PDL) space widths on the compression and tension sides were measured. Statistical Analysis All measurements were statistically analyzed with SPSS for Windows version 18.0 (SPSS Inc., Chicago, IL, USA). Repeated measures ANOVA and posthoc Tukey tests were used to compare the groups. Results No statistically significant difference was found with respect to the amount of tooth movement between the fluoridated and nonfluoridated groups (p > 0.05). Orthodontic force application increased the number of osteoblasts at the tension sides and reduced it at the compression sides (p < 0.001). An increased number of osteoclasts was observed in the nonfluoridated group relative to the fluoridated group (p < 0.01). Conclusions No difference was observed with respect to the amount of tooth movement between the fluoridated and nonfluoridated groups. Fluoride significantly reduced the number of osteoclasts in the experimental groups

    Relationship between orthodontic tooth movement and periodontal health: A journal review

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    The purpose of this journal review is to analyze the relationship between orthodontic tooth movement and periodontal health. During orthodontic treatment, tooth is moved into several movements, tooth is being intruded, extruded or up righted. Orthodontic treatment force induce an inflammatory reaction in the periodontium. This response is needed for orthodontic tooth movement. Orthodontic appliances may compromise oral hygiene conditions, leading to more bacterial formation. The equilibrium of microbial biofilms, immunological, and inflammatory host responses controls the course of periodontal disease. It is currently uncertain whether the periodontal alterations in orthodontic therapy could be reversible once appliances have been removed. Orthodontists need to understand the pre, during, and post treatment of their orthodontic treatment in relationship with patient’s periodontal health to prevent potentially permanent damages caused by orthodontic appliances. Conclusions: Effective collaboration provides an improved understanding of clinical issues and a better comprehension of the linkages between various disciplines, especially in orthodontics and periodontics. Particularly in patients using fixed appliances and periodontally susceptible individual, dental hygiene guidelines should be carefully observed
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